1. Field of the Invention
The present invention relates to a backlight controller and a method for controlling a backlight module, and more particularly, to a device and a method that adjust a backlight luminance of the backlight module to a target backlight luminance.
2. Description of Related Art
In recent years, flat panel displays, such as liquid crystal displays (LCDs), have enjoyed burgeoning development and flourished. Due to the numerous advantages of the LCD, such as low power consumption, free of radiation, and high space utilization, the LCD has become the main stream in the market. An LCD includes a liquid crystal display panel and a backlight module. The liquid display panel has no capacity of emitting light by itself so that the backlight module is arranged below the liquid display panel to provide the backlight for the liquid crystal display panel.
However, analyzing the electric power consumption of the LCD, the backlight module takes up 80% to 90% of the entire. For the large-size LCD panel, the LCD consumes considerable electricity. Generally, the image frame displayed on LCD panel may be light or dark, but actually, the electric power consumption of the backlight module is the same. That is to say the backlight module operates with 100% duty cycle whatever the image frames change. For this reason, many designers are devoted in saving electric power consumption of the backlight module.
One way to solve the said problem is to control the backlight luminance by referring the image. For example, the backlight luminance is decreased as the image is darker, and the backlight luminance is increased as the image is brighter. Nevertheless, if the image is extremely changed from one frame to another, the way of adjusting the backlight luminance causes unexpected backlight flicker due to the characteristics of different image frames.